Polymer composites are excellent candidates for parts that are in contact with steel in case of tribological sliding contact situations, e.g. slide bearing applications. Their high corrosion resistance and weight reduction capabilities while keeping a constant and low friction coefficient as well as anti-wear behavior are main advantages. Furthermore, the capability to “design” demanded properties using the right composition is beneficial. Although much research and development was performed in this field especially to find optimized material formulations there is still lack in fundamental understanding of these systems especially with respect to the role of transfer films. This work focusses to better understand fundamental formation and functional mechanisms and correlations with the structures of polymeric transfer films of a hybrid nanocomposite. Transfer film formation is an essential mechanism and feature to gain high performance and long life of sliding pairs under dry conditions. It is commonly know that thin and well distributed transfer films lead to beneficial tribological properties. A systematic experimental approach was done by systematically varying parameters in tribological exposures with the hybrid nanocomposite and a reference material. New insights were found by correlating the tribological results with transmission electron microscopy and energy-dispersive X-ray spectroscopy analysis. The compression of wear debris on the metal counterbody, decarburation by high local pressure and temperature as well as tribo-induced sintering effects were found as essential mechanisms. On the contrary, tribo-induced corrosion turned out to be a competing mechanism, which needs to be controlled, as it leads to unfavorable tribological performance. These mechanisms were verified by modelling approaches using the method of movable cellular automata.